Ken, I was fussing with that last post, and its out of order now...
For me, the quintisential "mountain" rifle has got to be something akin to what we call a "Bean".
Long, hand forged and usually swamped barrel, commercial round tail lock, usually percussion, but not always. Pronounced grip rail on the iron trigger guard, long tang, minimal side plate and often just a washer or shaped piece of iron acting as one, iron butt plate, iron nose cap, formed sheet iron thimbles and entry pipe,, stock pinned to a generally full stock, but mountain half stocks do exist...(the McKee rifles for instance...) a single lock bolt, and the iron joined where needed with sweat copper. Patch box optional, grease hole common, and hand made iron set triggers held in place by the trigger guard, not a tang bolt.
Any of those traits can be omitted as necessity or habit required, or what the makers had for skill or materials, but when I think southern mountain rifle, those are the main traits I think of. I think in my opinion it all culminated and zienithed in Unicoi county in the mid 1800s. At least thats what I "thought" it was all building to, and there were many good and not so good examples made along the way. (I say "thought", because i really think Ian is picking up the ball and advancing the school now quite a bit...as did Woodburry, and its great to see. )
Anyway, thats what I think of when I think southern mountian rifle....
T.C.Albert